implement github oauth and display user's name and avatar from it

lib/entendu_web/controllers/auth_controller.ex

@@ -0,0 +1,41 @@
+defmodule EntenduWeb.AuthController do
+  @moduledoc """
+  Auth controller responsible for handling Ueberauth responses
+  """
+
+  use EntenduWeb, :controller
+
+  plug Ueberauth
+
+  alias Ueberauth.Strategy.Helpers
+  alias Entendu.UserFromAuth
+
+  def delete(conn, _params) do
+    conn
+    |> put_flash(:info, "You have been logged out!")
+    |> clear_session()
+    |> redirect(to: "/")
+  end
+
+  def callback(%{assigns: %{ueberauth_failure: _fails}} = conn, _params) do
+    conn
+    |> put_flash(:error, "Failed to authenticate.")
+    |> redirect(to: "/")
+  end
+
+  def callback(%{assigns: %{ueberauth_auth: auth}} = conn, _params) do
+    case UserFromAuth.find_or_create(auth) do
+      {:ok, user} ->
+        conn
+        |> put_flash(:info, "Successfully authenticated.")
+        |> put_session(:current_user, user)
+        |> configure_session(renew: true)
+        |> redirect(to: "/")
+
+      {:error, reason} ->
+        conn
+        |> put_flash(:error, reason)
+        |> redirect(to: "/")
+    end
+  end
+end

lib/entendu_web/controllers/link_controller.ex

@@ -0,0 +1,11 @@
+defmodule EntenduWeb.LinkController do
+  @moduledoc """
+  Controller responsible for managing links responses
+  """
+
+  use EntenduWeb, :controller
+
+  def just(conn, _params) do
+      render(conn, "just.html")
+  end
+end

lib/entendu_web/controllers/page_controller.ex

@@ -0,0 +1,11 @@
+defmodule EntenduWeb.PageController do
+  @moduledoc """
+  Static page controller
+  """
+
+  use EntenduWeb, :controller
+
+  def index(conn, _params) do
+    render(conn, "index.html", current_user: get_session(conn, :current_user))
+  end
+end